Base Roster Total: 73
DLC Roster Total: 78
Unique Newcomers: 12
Base Third Party Newcomers: 2
Overall Third Party Newcomers: 3
Clone Newcomers: 1
Returning Cut Characters: 2
Total Cuts: 0
Captain Toad: The newcomer I am most confident in, Captain Toad has appeared in every mainline Mario title since Super Mario Galaxy, and has now gotten his own spinoff game for Wii U, 3DS, and Switch. The character would be the first small-bodied heavy-weight and would rely on a good ground game and projectiles, but would have a lackluster recovery.
Dixie and Cranky Kong: This may be the most bold of my additions, but it can be substituted for the safer choice of solo Dixie Kong if that's preferred. However, I am going to make the prediction that Sakurai will take note of the demand for Dixie Kong and decide to add her with the mechanic he considered for Diddy and Dixie in Brawl. I am assuming that this mechanic is similar to the Ice Climbers, but with the two characters using joint attacks, reminiscent of the Ice Climbers' up special. For example, Dixie would hold Cranky for their up special as she twirls her hair, and Cranky would flail around, hitting opponents beneath them. The two characters would act as a single fighter with a shared percentage bar, but they could feasibly have a mechanic where one can be KO'd while the other lives on, but without the ability to do certain attacks. This would represent the team-up mechanics of the Donkey Kong series, and would offer a unique experience to players.
Sheriff: The oldest video game character of Nintendo, Sheriff would be the embodiment of Nintendo's early arcade roots. Having his trusty pistol, his horse, his rope, and other Western gear to battle, Sheriff would be a character that attacks from a distance. His gimmick would be his ability to angle his entire kit in eight directions, similarly to Fox and Falco's up-special. This hearkens back to his home game, which allow him to move and aim in eight directions simultaneously. Sheriff fulfills the historical/legacy character quota that Sakurai seems to have (Mr. Game and Watch, R.O.B., Duck Hunt) and brings the first character of Shigeru Miyamoto into the esteemed world of Smash Bros. to duel with his descendants.
Ice Climbers: The Ice Climbers return as they were in previous games. I believe that they are the single most likely fighter to make it in who we haven't had explicitly confirmed.
Takamaru: After being considered since Melee, Takamaru finally reveals himself to the Smash Bros. crew, bringing all his abilities with him: Iaijutsu techniques with his katana, various types of shuriken, fireballs, a cloak of invisibility, and more. His play-style is extremely offensive, doing damage from a distance and killing up-close. He is also a master at deflecting physical projectiles with his sword, making him the ultimate projectile counter. His downfall is his mediocre recovery, poor grab-game, light weight, and difficulty killing from a distance, but he more than makes up for these with his speed, damage output, and powerful sword draws.
Ridley: While I fully acknowledge the risk of predicting Ridley, I suspect that Sakurai took note of the outcry when he was not playable yet again, and came back to revisit the idea of making him playable. While it's not a guarantee by any means, I hope that Sakurai has decided he can make Ridley work as a large, but light character who excels in the air despite his slowness on the ground.
Bandana Dee: Bandana Dee is a relatively simple addition to the roster, but manages to be an archetype we haven't seen - a small, lightweight spear user. Essentially a blend between Marth and Kirby, Bandana Dee attacks with stabbing motions that are most powerful at the spear's head. He excels at keeping opponents out with his disjoints, but he is extremely vulnerable up-close.
Wolf: Wolf returns essentially as he was in Brawl, but notably keeping a slow fall speed despite his above-average running speed.
Decidueye: While I'm not confident in any particular Pokemon character, I'm most convinced by this Ghost/Grass archer from Sun and Moon. A character that prefers sniping and precision shots over in-your-face attacks, Decidueye is remarkably adept at shooting projectiles from the air. He is fairly large and light, fast-falling, and slow on the ground, but his projectiles are capable of killing both up-close and from a distance. This Pokemon marks the first true archer in the Smash Bros. series.
Isabelle: The most lovable assistant you could ask for is a character I was initially hesitant on predicting. However, I've decided that Isabelle has a solid chance due to her extreme popularity among even casual fans. Isabelle acts as a terrain-modifying character - she uses furniture and public works projects to beautify her surroundings, including planting flowers that you had better not step on. Isabelle really doesn't mean to be hurting anyone, but she's a bit clumsy, dropping her supplies and not watching where she puts things. As a fighter, though, she's extremely good at forcing her opponents into situations that they aren't used to being in. Imagine Pac-Man's hydrant, but multiple large ones that can't be destroyed. She doesn't hit hard, but boy is she a great builder.
Alph: The only clone I actively expect. I imagine Alph playing similarly to Olimar, but with some key differences. Namely, Olimar is given his up special from Brawl, and Alph gets the Flying Pikmin as an up special. Further, while Olimar has Purple and White Pikmin, Alph has Flying Pikmin (who act like typical Pikmin, but go in a straight line when thrown) and Rock Pikmin (which have poor throws, but do amazing damage to shields.) Olimar's up-special needs to be improved significantly, but will not prove to be a nerf to him, as Pikmin numbers have been increased back to Brawl's.
Elma: I've mentioned several times before that I expect Elma to be added to represent the X side of the Xenoblade franchise, as Rex's game didn't come out until after the planning period for this game finished. Elma is a fierce fighter who carries dual swords and pistols. Speedy on the ground and with good air mobility, Elma's biggest weakness is taking hits, not dishing them out. She's light and has a below-average recovery, but hits hard, fast, and often. She could optionally be given an Overdrive mechanic; a meter fills up as time goes by and, when filled, can be activated to negate cooldown on Elma's moves.
Inklings: Do I really need to explain?
Bomberman: Given Konami and Nintendo's recent working relationship (Super Bomberman R) and Bomberman's modest popularity, I imagine we'll be seeing him as one of our third party representatives. That said, I'm not confident on him, as there's a lot of competition among third parties.
Rayman: Easily the most likely third party in my eyes, as Ubisoft and Nintendo have been closer than ever. Rayman being included only makes sense. He appeared last game as a trophy and has had his company working directly with Mario since then, producing several games in the Switch's first year. If he's not in, it's not due to Ubisoft and Nintendo's relationship.
Spring Man + Rex: I'll group these two together, as they are DLC for similar reasons. Both are extremely popular characters from games that released after the character selection process had finished. They are prime for DLC.
Sora: While definitely a risky choice on my end, I've come to the conclusion that Sora was high on the ballot. I've talked with many, many casual friends of mine, and it's astounding how many of them voted for Sora. That said, I expect him to be DLC, as that would make negotiations easier with Disney. If he's paid DLC, then Disney simply takes a cut of the sales, which is easier to manage than figuring out a lump sum to pay for the rights to have him in the base game. That said, he's certainly not a lock, and I wouldn't be surprised to not see him.
Pokemon + Fire Emblem: I am not certain yet, but I wouldn't be surprised to see the new protagonist of the 2018 Fire Emblem game and a new Pokemon being added as tie-ins for the release of the games, similarly to how Corrin was chosen.